For persons who either voluntarily or involuntarily must spend time in harsh environments, such as in bodies of water or in harsh lands, which often have temperature extremes, body heat loss or gain is a serious concern. In the case of persons being in forced to remain in water, especially cold water, heat loss is an extremely grave problem. In water environments exposure to dangerous fauna, such as sharks, sea snakes, venomous jelly fish, and the like is another threat. For military personnel who find themselves in enemy territory, for example downed pilots, another fear is discovery by the body heat signatures of their target. While at time it is desirable to be "IR invisible", at times, it is also desirable to have a highly visible signaling means, such as a large section of brightly colored material, so that the victim can wave down rescue forces.
In the past there have been various attempts to address some of these concerns. U.S. Pat. No. 3,695,507 to Sams to discloses a survival bag in the form of a bag fabricated from plastic film having a metallic coating. The bag of Sams is disclosed to be made from a single sheet of folded plastic to form a sealed, waterproof bag. The top edge of the bag can be folded over to form a channel to carry a draw cord or tape to enable the opening to be closed or partially closed. Also disclosed is the possibility of sandwiching a layer of aluminum between two layers of plastic for maximum heat reflection. Sams notes its bag can be reversed to either reflect body heat in, or reflect outside heat out, and opening the top to adjust the temperate inside the bag. Sams does not disclose any IR cloaking capabilities, the ability of a user to use the bag in the water, providing the survival bag in a sealed vacuum pouch to minimize its size and storage life, utilizing a bright contrasting color on a non-reflective coated side, or placing a hook on a drawstring at the mouth of the bag so that several persons in the bags in water can be tethered together in a group, even in heavy seas.
U.S. Pat. No. 2,931,043 to Achner discloses a salving-bag used to wrap up an injured person before and while being carried. It is said to be light weight, manufactured to provide a waterproof and airtight envelope, the inside of which is lined with a coat of aluminum or similar material. It discloses a drawstring at the top. This bag also includes a zipper. As with Sams, Achner fails to disclose any IR cloaking capabilities, an in-water use of use of the bag, providing the survival bag in a sealed vacuum pouch to minimize its size and storage life, contrasting colors on the inside and outside of the bag, and/or hooks to permit multiple bags to be linked together.
U.S. Pat. No. 3,708,810 to Merikallio discloses a protective blanket made from thin and flexible material impermeable to wind and moisture, with one surface being metallically glossy and thus reflective for thermal radiation, the other surface carrying transverse straps through which poles can be inserted to convert the blanket into a stretcher for injured persons. Merikallio discloses that the aluminized surface of the blanket furnishes a light-reflective marker on the ground, and one that can serve as a radar reflector both on land and at sea. Merikallio also discloses that one side of the blanket can be aluminum pigment coated and the outer surface can be finished, for military use, in camouflaging colors.
U.S. Pat. No. 4,790,040 to Grilliot et al discloses a large zippered bag for carrying a person wearing bulky clothing and booth contaminated by hazardous waste.
There accordingly remains a need for an emergency survival bag which has IR cloaking capabilities, has good thermal retention properties, can be used while a person is in the water, is small and light enough to be easily carried and stored, yet large enough when deployed for a person or persons to enter, wearing gear, boots, packs, life vests, and the like, and has a high visibility mode and a camouflaging mode.